The present disclosure relates to a gas injection unit and a thin film deposition apparatus having the same, and more particularly, to a gas injection unit that is configured to inject an organic material after vaporizing the organic material and a thin film deposition apparatus having the gas injection unit.
Generally, an organic light emitting device (OLED) is a display device that displays a desired image using a property of an organic light emitting material that is self-emissive when a voltage is applied thereto. The OLED is basically structured such that a pair of transparent and counter electrodes are stacked on a glass substrate and an organic thin film is inserted between the electrodes. Here, the organic thin film is formed by stacking a hole injection layer, a hole carrying layer, a light emitting layer, and an electron carrying layer to carry the electrodes and holes and emit light.
Unlike an inorganic material, the organic material used for forming the organic thin film does not require high vapor pressure and is easily dissolved and denaturalized at a high temperature. By this property of the organic material, in a related art, the organic thin film is deposited on the substrate through a process for charging the organic material in a pot formed of tungsten and vaporizing the organic material. However, in recent years, since there is a limitation in performing the process such as a limitation in an amount of the deposition material that can be stored in the pot, an injector with a heater has been used. The organic material is supplied to the injector and vaporized by the heater, after which the injector injects the vaporized organic material to the substrate.
However, each of a variety of stacked thin films of the OLED are deposited by vaporizing powders of different organic materials. Therefore, a related art method for manufacturing the OLED includes supplying a first organic material to the injector through a supplying tube, vaporizing the supplied first organic material, and injecting the first organic material to the glass substrate to deposit the thin film, after which supplying a second organic material to the injector, vaporizing the second organic material, and injecting the second organic material to deposit another thin film on the previously form thin film. Theses processes are repeated to stack other thin films one another. Therefore, the organic material that is previously used remains in the supplying tube and thus the current organic material is mixed with the previously used organic material and injected. Therefore, there is a limitation in that a desired thin film cannot be deposited.
Meanwhile, the injector disposed in a chamber has an undersurface facing the substrate. The undersurface is approximately flat and provided with a plurality of injection holes opened toward the substrate and thus the injector injects the vaporized material in a direction perpendicular to a plane of the substrate.
However, there is a need to control an injection structure of the injector depending on the occasion. For example, when a process environment such a size of the substrate or a kind of the thin film alters, there is a need to change the injection structure of the injector to use a current process apparatus as it is or achieve an optimum yield. Further, there is also need to alter the injection structure of the injector to restore the deformation of the injector structure due to a temperature of an interior of the chamber. However, the related art injector has an injector structure that is fixed in an initial state and thus it is impossible to change or control the injection structure. Accordingly, there is a limitation in that, when the process environment is altered, the apparatus must be entirely changed.